CYPERACEAE 



151 



CYPERACEAE* 



Fertile flowers perfect. 



Basal empty scales of the spikelets none or not more than 

 two (except in Eriophorum). 

 Scales of the spikelets 2-ranked; bristles none. 

 Scales of the spikelets spirally imbricated. 



Base of the style persistent as a tubercle on the 

 achene. 

 Spikelet 1; culm leafless; bristles usually 



present. 

 Spikelets several or numerous; culms leaf- 

 bearing; bristles none. 

 Base of the style not persistent as a tubercle. 

 Flowers without any inner scales. 



Base of the style swollen; bristles none. 

 Base of the style not swollen; bristles 

 usually present. 

 Bristles 6-many, silky, much elongated. 

 Bristles short or little elongated, 

 smooth or barbed. 

 Flowers with one or more inner scales. 



Flowers with 3 broad, stalked scales alter- 

 nating with barbed bristles. 

 Flowers with 1-2 hyaline scales; bristles 

 none. 

 Flowers with 2 convolute inner scales. 

 Flowers with a single minute inner 

 scale. 

 Basal empty scales of the spikelets 3 or more. 

 Style 2-cleft. 



Spikelets breaking up into i-fruited joints; bristles 



present; sca'les 2-ranked. 

 Rachis of the spikelets not jointed, persistent; scales 

 spirally imbricated. 

 Spikelets few-flowered ; bristles usually present. 



Spikelets many-flowered; bristles none. 

 Style 3-cleft; bristles none. 

 All the flowers imperfect. 



Pistillate flower subtended by a flat scale; achene long. 

 Pistillate flower enclosed in a perigynium. 



1. Cyperus. 



2. Eleocharis. 



3. Stenophyllus. 



4. FlMBRISTYLIS. 



5. Eriophorum. 



6. Scirpus. 



7. Fuirena. 



8. Lipocarpha. 



9. Hemicarpha. 



10. dulichium. 



11. Rynchospora. 



12. psilocarya. 



13. Mariscus. 



14. Scleria. 



15. Carex. 



1. Cyperus L. 



Style 2-cleft; achene lenticular, not 3-angled; scales falling from 

 the rachis; spikelets flat. 

 Spikelets yellow; superficial cells of the achene oblong. 1. C. flavescens. 



* Taxonomic treatment, except the genus Carex, contributed by Dr. N. L. Britton. 



